Superchick stimulates the proliferation of cultured chicken cells. The receptor that binds Superchick is a receptor tyrosine kinase, and many tumor cell lines have mutations in the gene that encodes this receptor. Which of the following types of mutations would be expected to induce uncontrolled cell proliferation?
a. A mutation that increases recognition of the receptor by phosphatases
b. A mutation that prevents ligand binding.
c. A mutation that prevents localization of the receptor to the plasma membrane.
d. A mutation that causes dimerization of the receptor
e. A mutation that destroys the kinase activity of the receptor
